1. Field of the Invention
The present invention relates to a vehicle in which a pair of driving wheels are disposed on both left and right sides of a vehicle body frame.
2. Description of the Prior Art
In the past, in a vehicle of this kind, a wheel driving shaft is laterally mounted between a pair of driving wheels, and a transmission device for transmitting power of the engine is connected to a central portion of the driving shaft, and therefore, a body space is reduced by the presence of the transmission device, resulting in a certain limitation in an attempt of making the vehicle smaller while securing a predetermined body space.
Furthermore, the aforesaid power transmission device is composed of a transmission driven by an output shaft of the engine and a differential device driven by the transmission to distribute power to a plurality of driving wheels in response to a rotational speed difference therebetween, and therefore becomes complicated in construction.
In addition, in a vehicle having a pair of left and right driving wheels, for example, in a four wheel automobile, a supporting device for power units, a driving device for the driving wheels and a suspension device for the same are independent from each other and therefore, become complicated in construction.
Moreover, in the above-described vehicle, when the driving wheels are moved up and down, a large relative displacement occurs between the power unit and the body frame, and therefore, all pipe lines such as an intake system including a carbureter, an exhaust system including an exhaust muffler and a cooling system including a radiator are carried by the power unit. With this arrangement, however, the weight under springs is increased by said pipe lines to tend to lower somewhat the road surface follow-up properties of the driving wheels and a large movable space for the aforesaid pipe lines has to be secured, and therefore, various considerations in design are required.
In view of the foregoing, it can be considered that in order that a part of the pipe line is carried by the body frame, the pipe line is divided into a portion extended from the power unit and a portion supported on the body frame, and said portions are connected by a flexible joint. However, this flexible joint is relatively heavy, which is not suitable for a ligbt-weight vehicle.